diff --git a/internal/runtime/executor/claude_executor_cloaking.go b/internal/runtime/executor/claude_executor_cloaking.go
index af1e9afd1..ac4cb068b 100644
--- a/internal/runtime/executor/claude_executor_cloaking.go
+++ b/internal/runtime/executor/claude_executor_cloaking.go
@@ -1247,20 +1247,40 @@ func countCacheControls(payload []byte) int {
 
 // stripCacheControls removes Anthropic-only prompt-caching fields before a
 // delegated Claude-format request is sent to a provider that does not support
-// them, such as Kimi.
+// them, such as Kimi. It only targets protocol-level cache_control markers on
+// system/tool/message blocks and nested content blocks (e.g. tool_result
+// content); arbitrary JSON like tool input_schema properties named
+// "cache_control" are left untouched.
 func stripCacheControls(payload []byte) []byte {
 	result := payload
+	for i := range gjson.GetBytes(result, "system").Array() {
+		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("system.%d.cache_control", i))
+		result = stripContentCacheControls(result, fmt.Sprintf("system.%d.content", i))
+	}
 	for i := range gjson.GetBytes(result, "tools").Array() {
 		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("tools.%d.cache_control", i))
 	}
-	for i := range gjson.GetBytes(result, "system").Array() {
-		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("system.%d.cache_control", i))
+	for i := range gjson.GetBytes(result, "messages").Array() {
+		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("messages.%d.cache_control", i))
+		result = stripContentCacheControls(result, fmt.Sprintf("messages.%d.content", i))
 	}
-	for messageIndex, message := range gjson.GetBytes(result, "messages").Array() {
-		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("messages.%d.cache_control", messageIndex))
-		for contentIndex := range message.Get("content").Array() {
-			result, _ = sjson.DeleteBytes(result, fmt.Sprintf("messages.%d.content.%d.cache_control", messageIndex, contentIndex))
-		}
+	return result
+}
+
+// stripContentCacheControls removes cache_control from each block in a content
+// array and recurses into nested content arrays (e.g. a tool_result whose
+// content is an array of text/image blocks). It does not walk into siblings of
+// content such as tool_use input or tool input_schema.
+func stripContentCacheControls(payload []byte, contentPath string) []byte {
+	result := payload
+	arr := gjson.GetBytes(result, contentPath)
+	if !arr.IsArray() {
+		return result
+	}
+	for i := range arr.Array() {
+		itemPath := fmt.Sprintf("%s.%d", contentPath, i)
+		result, _ = sjson.DeleteBytes(result, fmt.Sprintf("%s.cache_control", itemPath))
+		result = stripContentCacheControls(result, fmt.Sprintf("%s.content", itemPath))
 	}
 	return result
 }
diff --git a/internal/runtime/executor/claude_executor_test.go b/internal/runtime/executor/claude_executor_test.go
index 5b1c7a715..e126ee898 100644
--- a/internal/runtime/executor/claude_executor_test.go
+++ b/internal/runtime/executor/claude_executor_test.go
@@ -6452,3 +6452,53 @@ func TestClaudeExecutor_CacheTTLIsPairedWithExtendedCacheTTLBeta(t *testing.T) {
 		})
 	}
 }
+
+func TestStripCacheControls(t *testing.T) {
+	payload := []byte(`{"model":"claude-opus-4","system":[{"type":"text","text":"sys","cache_control":{"type":"ephemeral"}}],"tools":[{"name":"t","cache_control":{"type":"ephemeral"},"input_schema":{"type":"object","properties":{"cache_control":{"type":"string"}}}}],"messages":[{"role":"user","content":[{"type":"text","text":"hi","cache_control":{"type":"ephemeral"}},{"type":"tool_use","tool_use_id":"tu_1","name":"tool","input":{"cache_control":{"type":"string"}}}],"cache_control":{"type":"ephemeral"}}]}`)
+	got := stripCacheControls(payload)
+
+	for _, path := range []string{
+		"system.0.cache_control",
+		"tools.0.cache_control",
+		"messages.0.cache_control",
+		"messages.0.content.0.cache_control",
+	} {
+		if gjson.GetBytes(got, path).Exists() {
+			t.Fatalf("cache_control still present at %q: %s", path, got)
+		}
+	}
+	// cache_control inside a tool input_schema or tool_use input is data,
+	// not an Anthropic marker.
+	if gjson.GetBytes(got, "tools.0.input_schema.properties.cache_control.type").String() != "string" {
+		t.Fatalf("tool input_schema property cache_control should be preserved, got %s", got)
+	}
+	if gjson.GetBytes(got, "messages.0.content.1.input.cache_control.type").String() != "string" {
+		t.Fatalf("tool_use input property cache_control should be preserved, got %s", got)
+	}
+	if gjson.GetBytes(got, "system.0.text").String() != "sys" {
+		t.Fatalf("system text not preserved, got %s", got)
+	}
+	if gjson.GetBytes(got, "messages.0.content.0.text").String() != "hi" {
+		t.Fatalf("message content not preserved, got %s", got)
+	}
+}
+
+func TestStripCacheControls_NestedToolResultContent(t *testing.T) {
+	payload := []byte(`{"model":"claude-opus-4","messages":[{"role":"user","content":[{"type":"tool_result","tool_use_id":"tu_1","content":[{"type":"text","text":"result","cache_control":{"type":"ephemeral"}}],"cache_control":{"type":"ephemeral"}}]}]}`)
+	got := stripCacheControls(payload)
+
+	for _, path := range []string{
+		"messages.0.content.0.cache_control",
+		"messages.0.content.0.content.0.cache_control",
+	} {
+		if gjson.GetBytes(got, path).Exists() {
+			t.Fatalf("cache_control still present at %q: %s", path, got)
+		}
+	}
+	if gjson.GetBytes(got, "messages.0.content.0.tool_use_id").String() != "tu_1" {
+		t.Fatalf("tool_use_id not preserved, got %s", got)
+	}
+	if gjson.GetBytes(got, "messages.0.content.0.content.0.text").String() != "result" {
+		t.Fatalf("nested tool_result content not preserved, got %s", got)
+	}
+}